Electric switch and circuit-breaker.



PATENTED AUG. 23, 1904.

A. J. HORTON. ELECTRIC SWITCH AND CIRCUIT BREAKER.

APPLICATION FILED JAN. 16. 1904.

N0 MODEL.

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a a/M .21 gm A Z456 r61 15%72072 7% UNITE STATES Patented August 23, 19 14.

PATENT OEEIcE.

PORATION OF \VISOONSIN.

YORK, ASSIGNOR TO THE MILWAUKEE, \VISOONSIN, A COR- ELECTRIC SWITCH AND CIRCUIT-BREAKER.

SPECIFICATION forming part of Letters Patent No. 768,227, dated Augu 23, 1904. Application filed January 16, 1904. Serial No. 189,308. (No model.)

To all whom it may concern:

Be it known that I, ALBERT J. HORTON, a citizen of the United States of America, and a resident of hiteplains, county of IVestchester, and State of New York, have invented certain new and useful Improvements in Electric Switches and Circuit-Breakers, of which the following is a specification.

This invention relates to a circuit-breaker for electric current, and is designed especially for the emergency interruption of motor-armature circuits.

It is combined with a hand-operated motor starting and controlling switch by which the motor is started, controlled, and stopped in such manner that upon the operation of the circuit-breaker from any cause it cannot be closed until the starting-switch has been re stored to its starting position.

The specific emergency device which is herein disclosed is an under-potential magnet arranged to open the circuit-breaker when the line potential falls materially or the supply of current ceases.

In the accompanying sheet of drawings, which forms a part of this specification, the figure is a front View of a slate with the circuit-breaker, starting-switch, and other apparatus mounted thereon, and combined with this is a diagram of the circuits therefor.

The apparatus illustrated comprises a motor M, which is supplied from two leads A B through a line-switch L, a motor starting and controlling switch and rheostat, and an independent circuit-breaker for opening the armature-circuit in an emergency such as arises upon the failure of current through the operation of an under-potential relay-magnet, which will be described in detail later. The motor has a shunt field which in this drawing is independent of the contacts of the rheostat and motor-starting switch and the circuit-breaker and is connected directly to the leads inside the line-switch, so that it will be open only when the line-switch is open.

A slate slab 1 carries a metal stud 2, on which a lever 3 is fulcrumed. The lever is provided with an operating-handle 4 and is operated across a series of rheo'stat-contacts 5. Resistance-sections 6 are connected to these contacts. The slate also carries a circuit-breaker consisting of two contact-posts 7 8 andpreferably a pile of strips of sheetcopper 9 for bridging between the posts. This bridging-piece is carried by the armature of a relay-magnet 10, also mounted on the slate. IVhen the magnet is energized, the bridging-piece is drawn against the posts and electrical connection is established between the posts, through which current is admitted to the armature. The relay-magnet is in the form of a solenoid, and a stem 11, of nonmagnetic material, is connected to the armature and moves. with the armature and circuit-breaker. This stem projects through the upper end of the relay-magnet. Its use will be discussed later;

The relay-magnet is energized by a controlling-circuit between the supply-leads which is independent of the armature-circuit.

- As illustrated, it is connected directly between the leads, and hence the magnet is wound with a great number of turns of fine wire, so

as to have a sufliciently-high resistance to withstand the voltage used. The magnet re ceives current directly from the supply-leads and is so adjusted that its armature will be released if there is any material fall in the potential between the supply-leads or cessation in the supply of current. The magnet therefore acts as an under-potential emergency device to disconnect the motor-armature from the line.

henever the circuit-breaker is operated by reason of the failure of current through the relaymagnet and the motor-starting lever is at a running position either toward the position?) for forward operation of the motor or toward the position 3" for reverse operation of the motor, a latch 12 mechanically engages a collar 13 on the stem 11 and prevents the closure of the circuit-breaker until the motorstarting switch-lever has been brought toward or restored to the initial position 3 sufficiently to engage an arm 1 of the latch and withdraw the latch. This arm is engaged by an insulated stud or roller 15 projecting from the lever. The circuit-breaker falls by gravity to its open position when released by the relay-magnet, and the latch falls by gravity into locking engagement with the collar on the stem.

What I claim as new, and desire to secure by Letters Patent of the United States, is

The combination of a hand-operated motorstarting switch, an electrically-operated circuit-breaker, a motor-armature circuit containing the motor-starting switch and circuitbreaker in series, a relay-magnet for closing and holding the circuit-breaker in closed po- 

